Module: ppl/ppl Branch: master Commit: 96604c0b36129ddc2ab6079a11c3babfb4dc69cd URL: http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=96604c0b36129...

Author: Enea Zaffanella zaffanella@cs.unipr.it Date: Sun Dec 19 12:05:02 2010 +0100

Added a workaround to a space efficiency bug affecting MIP_Problem. The baseline patch has been contributed by Marco Poletti.

MIP_Problem now stores the input constraints as a sequence of Constraint*. In this sequence, we distinguish between owned constraints (whose resources are under control of the current MIP_Problem object) and inherited constraints (whose resources are shared with, and owned by, another MIP_Problem object). When starting a branch-and-bound computation looking for an integral feasible/optimal solution, we now inherit (rather than copy) the input constraints.

The workaround greatly improves space/time efficiency on (mixed) integral problems, also providing a (simple and reasonable) partial solution to

https://www.cs.unipr.it/mantis/view.php?id=62

The solution is still partial: a complete solution requires the implementation of a backtracking mechanism for incrementally added constraints.

---

src/MIP_Problem.cc | 78 +++++++++++++++++----- src/MIP_Problem.defs.hh | 90 ++++++++++++++++++++++++-- src/MIP_Problem.inlines.hh | 147 ++++++++++++++++++++++++++++++++++++++++-- src/MIP_Problem.templates.hh | 6 +- 4 files changed, 288 insertions(+), 33 deletions(-)

Diff: http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commitdiff;h=96604c0b3...